Muscles Stretched by Yoga Asanas

When you do certain yoga asanas -- or postures -- you can feel certain groups of muscles lengthening together like a thick rubber band. Learning what muscle groups you are stretching can help you understand your body better, but memorizing each muscle group can be a pain if you aren't familiar with human anatomy. Instead of memorizing each muscle, group them together in myofascial lines, which are groups of muscles that share many nerve and connective tissue pathways, according to massage therapist Thomas Myers, author of "Anatomy Trains." When one group of muscles is lengthened or contracted, it will affect how another group of muscles functions that runs along the same or nearby paths. Learning the myofascial lines first will make identifying what muscles you are stretching easier.

Superficial Back Line

The superficial back line consists of muscles and tendons in the bottom of your feet, calves, hamstrings, erector spinae and the galea aponeurotica -- a sheathe of tough connective tissue that runs from the base of your skull to the crown of your head. You can feel this group of muscles and tissues lengthen when you do Downward Dog, Hastapadasana -- or the Standing Forward Bend -- and Halasana -- Plow pose.

Superficial Front Line

The superficial front line works in opposition with the superficial back line. This line consists of the muscles and tendons on the top of your feet and toes, tibialist anterior, quadriceps, rectus abdominis, pectoralis major and the sternocleidomastoid. You can feel this entire line or parts of this line stretch when you do Bow pose, Cobra pose, Reverse Warrior pose and Standing Back Bend.

Lateral Line

The lateral lines function as stabilizers on each side of your body to keep it upright and in balance like a pair of pillars. The lateral lines consist of the lateral peroneals in your lower leg, iliotibial band, tensor fasciae latae, gluteal complex, external and internal obliques, intercostal muscles in your ribs, splenius cervicis, sternocleidomastoid and scalenes. There aren't very many asanas that solely address the lateral line. Sample asanas include Half Moon pose and Triangle pose.

Spiral Line

When you swing a golf club or throw a baseball, the spiral line is involved in the movement pattern. The myofascial line wraps around your torso like a Miss America sash diagonally on each side of your body. It consists of the splenis capitis, rhomboids, external and internal obliques, tensor fasciae latae, iliotibial band, anterior tibiallis, peroneus longus, biceps femoris and erector spinae. Asanas that address the spiral line include Chakrasana -- or Lying Body Twist -- and Sitting Half Spinal Twist.

Arm Lines

When you reach your arms overhead in a standing position, you can feel your chest and upper back muscles stretch as well. There are two arm lines -- one in the front of your body and one in the back. The front arm line extends from your pectoralis major, through your arms and into your palms and fingers. These muscles include the biceps, pectoralis minor, flexor muscles of the forearm and the thenar muscles of your thumbs. The back arm line extends from the thoracic and cervical spine, through the back of your arms and into the back of your hands and fingers. These muscles include your trapezius, deltoids, triceps, extensors in your forearm and hypothenar muscles at the "blade" of your hand just below your fifth finger. Many yoga asanas address the arm lines, including Sun Salutation, Warrior pose and Half Moon pose.